From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 958B5C43381 for ; Wed, 17 Feb 2021 14:18:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6B45264E5B for ; Wed, 17 Feb 2021 14:18:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233383AbhBQOSy (ORCPT ); Wed, 17 Feb 2021 09:18:54 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]:2581 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232371AbhBQOSv (ORCPT ); Wed, 17 Feb 2021 09:18:51 -0500 Received: from fraeml715-chm.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4DgfwT1hRjz67qL6; Wed, 17 Feb 2021 22:14:17 +0800 (CST) Received: from lhreml710-chm.china.huawei.com (10.201.108.61) by fraeml715-chm.china.huawei.com (10.206.15.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Wed, 17 Feb 2021 15:18:08 +0100 Received: from localhost (10.47.29.73) by lhreml710-chm.china.huawei.com (10.201.108.61) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2106.2; Wed, 17 Feb 2021 14:18:06 +0000 Date: Wed, 17 Feb 2021 14:16:59 +0000 From: Jonathan Cameron To: Ben Widawsky CC: , , , , , Bjorn Helgaas , "Chris Browy" , Christoph Hellwig , "Dan Williams" , David Hildenbrand , David Rientjes , Ira Weiny , "Jon Masters" , Rafael Wysocki , Randy Dunlap , Vishal Verma , "John Groves (jgroves)" , "Kelley, Sean V" , kernel test robot , Stephen Rothwell , Al Viro Subject: Re: [PATCH v5 4/9] cxl/mem: Add basic IOCTL interface Message-ID: <20210217141659.000064ec@Huawei.com> In-Reply-To: <20210217040958.1354670-5-ben.widawsky@intel.com> References: <20210217040958.1354670-1-ben.widawsky@intel.com> <20210217040958.1354670-5-ben.widawsky@intel.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; i686-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.47.29.73] X-ClientProxiedBy: lhreml704-chm.china.huawei.com (10.201.108.53) To lhreml710-chm.china.huawei.com (10.201.108.61) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 16 Feb 2021 20:09:53 -0800 Ben Widawsky wrote: > Add a straightforward IOCTL that provides a mechanism for userspace to > query the supported memory device commands. CXL commands as they appear > to userspace are described as part of the UAPI kerneldoc. The command > list returned via this IOCTL will contain the full set of commands that > the driver supports, however, some of those commands may not be > available for use by userspace. > > Memory device commands first appear in the CXL 2.0 specification. They > are submitted through a mailbox mechanism specified in the CXL 2.0 > specification. > > The send command allows userspace to issue mailbox commands directly to > the hardware. The list of available commands to send are the output of > the query command. The driver verifies basic properties of the command > and possibly inspect the input (or output) payload to determine whether > or not the command is allowed (or might taint the kernel). > > Reported-by: kernel test robot # bug in earlier revision > Reported-by: Stephen Rothwell > Cc: Al Viro > Signed-off-by: Ben Widawsky > Reviewed-by: Dan Williams (v2) Reviewed-by: Jonathan Cameron